The speed your site responds to queries is used as part of the overall ranking algorithm – sites that don’t respond at all are likely to get dropped from search engine indexes. Therefore turning on any performance enhancements you can is a must if you want to maintain rankings.

To that  end I’ve been working on performance on our sites. My previous post was about turning on PHP errors and correcting them. One page on an internal site went from taking a few minutes to render to under 20 seconds all because I had $$var instead of $var in one line in a loop. (For those not in the know about PHP, $$var causes $var’s value to be referenced, so if $var = ‘test’ then $$var is treated as $test).

So next up is MySQL performance. If you have a database driven site using MySQL (most Unix blogs are like this) then you’re almost sure to gain performance improvements from turning on MySQL cache. By following the recommendations at http://www.databasejournal.com/features/mysql/article.php/3110171 you will give a performance boost for your site. How much depends on what your site does. On a blog the performance improvement will be minor but over thousands of visitors it will add up to less disk activity overall. If you have a large database driven site doing number crunching (we have one of these) it can make a huge difference to response times.

I don’t know how this works on a shared host as all our hosts are either dedicated or VPS (virtual private servers). You may want to send the URL to your host to see if they will implement the necessary changes.